Furnace for heating pipes, cylinders, and the like



Dec. 29, 1931. c w u s 1,838,724

FURNACE FOR HEATING PIPES, CYLINDERS, AND THE LIKE Filed Sept. 11, 1929 2 Sheets-Sheet 1 7 6 M H k I I IL-x2", 4- 1- a a: 24 j I v- V r g IN VEN TOR. Fewvc C. ML 1/140 Dec. 29, 1931. F. c. WILLIAMS 1,838,724

, CYLINDERS, AND THE LIKE Filed Sept. 11, 1929 FURNACE FOR HEATING PIPES 2 Sheets-Sheet 2 I lfilllll/I II/IIIIIIII/Ar/millIIIIIIIIIIII/Ill/IllI/IIIIIlIlJ/l/llll/IIIIII/11111111111111!!! will/III!!! Patented Dec. 29, 1931 UNITED STATES PATENT OFFICE Application filed September 11, 1929. Serial No. 391,954.

The invention forming the subject matter of this ap lication relates to a furnace used in connection with the treatment of an ob ect, such as a pipe, with a heated li uid.

In the painting of certain o jects or the coating thereof with asphalt or other thlck liquid, it is necessar to heat the liquid mto which the object is ipped, and to lace the heated object into the heated aspha t whereby a minimum amount of asphalt will adhere to the object.

The primary object of the invention 1s the provision of an apparatus for treating an object with a heated solution or H uid, such asasphalt, and for heating said 0 ject before said treatment, the heating of said liquid and of the object being accomplished by the same source of heat.

Another object of the invention is the provision of an apparatus in which both the heating of a liquid into which an object is dipped and the heating of the object prior to dipping, may be readily accomplished by the use of the same heat, and without introducing any of the gases of combustion or a like substance, directly into the compartment in which the preheating of the object is accomplished.

Another object of the invention is the rovision of a furnace in which gases of com ustion are created and of a tortuous passage through which the gases of combustion are conducted to a tank heater for heating a liquid, and also the provision of a heating com-- partment related to the furnace in such manner that the heated air circulated through the com artment is also passed around a portion of t e said tortuous assage whereby it is heated to the desired egree without coming into direct contact with the gases of combustion, and also without necessitating the use of a separate heater for the heating compartment.

Another object of the invention is the provision of a dip tank containing liquid for the treatment of certain objects such as, pipes or machine parts, and 'a heating compartment in which the pipes and parts are heated before being dipped, heating means being provided common to both the diptank and the heating compartment, said heating means being so arranged as to directly heat said dip tank and to allow. the circulation of the heating air around a portion of the heating means without bringing the same in contact with the heating substance in said heating means. 4

Another object of the invention is the provision of a furnace in which the gases of combustion are passed through-a plurality of tubes and around the outer surface of a dip tank for heating a liquid in said dip tank, and then said gases of combustion are returned to a passage adj ment to the combustion chamber of the furnace for the purpose of being reheated and recirculated in a mixture with the gases of combustion originating from the chamber; a heating compartment being provided in operative relation to said furnace, and the heated air circulated in said compartment is also circulated around said tubes for heating the same, thereby effecting a great economy of fuel in the treatment of an object with the said heated liquid and in the drying of said object.

Other objects and advantages are to provide a furnace for heaters and the like, that will be superior in point of simplicity, inexpensiveness of construction, positiveness of operation, and facility and convenience in use and general efliciency.

In this specification and the annexed drawings, the invention is illustrated in the form considered to be the best, but it is to be understood that the invention is not limited to such form, because it may be embodied in other forms; and it is also to be understood that in and by the claims following the description, it is desired to cover the invention in whatsoever form it maybe embodied.

The invention is clearly illustrated in the accompanying drawings in which Fig. 1 is a somewhat diagrammatic view illustrating the passage of the gases of combustion from the furnace and around the di tank, part of the furnace walls and the tank ing shown in section;

Fig. 2 is an end view of the ap aratus showing the arrangement of the air c1rculating fan thereon;

Fig. 3 is another end view of the apparatus showin the arrangement of the gas circulating an thereon;

Fig. 4 is a side elevation of the entire a paratus, viewing Fig. 6 in the direction oft e arrows 44; a

Fig. 5 is a sectional view of the furnace portion of the apparatus, the as duct and the return duct leading to and rom the di tank being indicated in dotted lines, the sectlon being taken on the line 55 of Fig. 6;

Fig. 6 is a vertical section through the apparatus, the section being taken on the line 6-6 of Fig. 5;

Fig. 7 is a sectional view showing the relative arrangement of the heating compartment and the combustion chamber and of the return duct, the section being taken on the line 77 of Fig. 5;

Fig. 8 is a sectional view showing the arrangement of the heating compartment relatively to the firebox and the gas conduits of the apparatus, the section being taken on the line 8-8 of Fig. 5.

My device in its general organization, comprises a furnace A, a tank heater B and a heating kiln C. The furnace A and the heating kiln C, are built in one unit, the dip tank B and its heating chambers may be also built in a unitary structure with the furnace or they may be located near by in a separate structure connected to the furnace by means of ducts to be hereinafter described in detail, said connection bein clearly shown in the diagrammatic view in ig. 1.

The furnace A comprises a combustion box 6 divided into a lower chamber 7 in which is disposed a gas burner 8 of the usual construction, and into an upper chamber 9 which is in communication with the lower chamber 7 at an opening 11, said opening being disposed at the end of the chamber 7 opposite to the burner 8. The gases of combustion originating in the lower chamber 7 flow through the opening 11 into the upper chamber 9 and escape from said upper chamber through an outlet opening 12, and into an outlet passage 13. Through the passage 13, the gases of combustion are conducted through fire tubes 14 at the outlet end of which tubes, is formed an outlet box 16. For the purpose of forcing circulation, a fan 17 is provided to the inlet of which is connected the outlet box 16, said fan discharging into a heater inlet duct 18. The inlet duct 18 introduces the gases into the dip tank heater B, from which the gases of combustion are returned through a return duct 19 into the furnace. The return duct 19 extends below the base of the whole apparatus and terminates in a vertical duct 21, which latter opens into the passage 13, as it is clearly shown in Fig. 7. It is to be noted that the passage 13 does not extend along side the whole height of the combustion box 6 but only along side the upper half thereof, corresponding to the upper chamber 9. Below the passage 13 is a return passage 22 extending alon side the lower chamber 7 of the combustion box 6. The vertical duct 21 returns the gases into both passages 13 and 22 and both passages carry the gases of combustion toward the inlet openings of the tubes 14. While in the up er chamber 13, the return gases immediate y intermix with the ases of combustion flowing from the upper 0 amber 9, the returned gases introduced into the lower passage 22 do not mix with the fresh gases of combustion until they travel through the whole length of the assage 22. During this travel, the returned gases of the lower passage 22 impinge directl upon the adjacent side of the lower cham er 7 of the combustion box 6, whereby the reheating of said returned gases is effected.

The tank heater B comprises an outer casing 23 having an inner tank 24 supported therein in the manner shown in Fig. 1, so as to form a heating chamber around the outer surface of the tank 24. The gases of combustion circulated in the chamber formed between the tank 24 and the casing 23, 've up part of their heat to the tank wall 24 t ereby .maintaining the content of the tank, such as asphalt or other liquid, at the desired temperature.

The circulation and recirculation of the gases of combustion is very economically accomplished through the aforedescribed connections of the furnace to the chamber of the tank heater B, by the operation of the fan 17.

The usual way of treating an object, such as a pipe or the like, for the purpose of coating the same with asphalt or other similar liquid, is to heat the object in the heating compartment 26, to a temperature of approximately 500 F. and then to dip said object into the heated liquid in the dip tank 24. The object, when heated, will have a minimum amount of the asphalt adhere thereto, in contradistinction to an unheated object which would absorb a maximum amount of asphalt. It is to be noted that the heating compartment 26 is formed directly below the furnace A, and that the horizontal portion of the return duct 19 extends below the bottom of the compartment 26. The particular location of the compartment 26 utilizes the heat radiating from the walls of the furnace and of the return duct 19, to raise the temperature within said compartment.

In order to achieve the complete heating of the object placed in the compartment 26, it is necessary to circulate heated air through said compartment. For this purpose the compartment 26 is provided with an inlet opening 27 and an outlet opening 28 disposed adjacent to the opposite ends of the compartment and in the top wall 29 thereof. A fan 31 is disposed above the inlet opening 27 and lob discharges through said inlet openin Above the top 29 of the com artment 26 is another wall 32 spaced from t e top 29 so as to form an air return passage '33 therebetween, the furnace A being supported above the upper wall 32.

The walls of the furnace A are so constructed as to form an air chamber 34 around the tubes 14. The bottom of said air chamr is open as at 36 and is in communication with the air return passage 33. In order to force the air to circulate around the outer surface of the tubes 14, vertical bafile plates 37 are secured upon the top 29 and extend to about half wa into the chamber 34. Another vertical bathe plate 38 depends from the top of the chamber 34 and is disposed between the baflie lates 37 so as to extend be ond the free en s of the bafiie plates 37. 'l hus the direct circulation of the air in the passage 33 is baflied and the air is deflected by said bafile plates so as to travel on a tortuous ath as indicated by the arrows in Fig. 6. e air during its passage through the chamber 34, impinges upon the Walls of the tubes 14 and is heated thereby.

The air return passage 33 is connected to the intake of the fan 31 as at 39. The circulation of the air through the kiln C is accomplished by the rotation of the fan 31, which forces the air through the inlet opening 27 and out through the outlet opening 28, through the chamber 34 and return passage 33, from which latter the fan withdraws the returned air and recirculates the same through the aforedescribed path of flow.

It is apparent that the gases of combustion do not escape into the chamber 34. However, during their passage toward the tank heater B, they give u a certain amount of heat to the air whic is circulated in the chamber 34. Therefore, both the heating of the liquid in the dip tank 24 and also the heating of the air to be circulated in the kiln C, is effected very esconomically by the same source of heat.

In order to allow the insertion of the object in the compartment 26 from either end of said compartment, the usual sliding doors 41 are suspended on pulleys 42, at the opposite ends of said openings.

In operation the article, such as a pipe, is heated to the desired degree in the kiln C, then one of the doors 41 is opened and the heated pi e is dipped in the tank 24. The

ipe is le in the said compartment 26 until heated by the circulation of said heated air. The fans 18 and 31 effectively cause the circulation respectively of the gases of combustion and of the heating air.

It will be recognized that a particularly compact apparatus is provided in which the rovision of separate heating elements for a kiln is entirely eliminated; the same source of heat supplies the heat around the dip tank bustion therethrough, the

so as to give up a certain amount of heat through the air circulated therethrough.'

The apparatus is of unitary character, it does not require any careful adjustment and the different operations connected with the heating and dipping of an article may be readily accomplished therein with great facility and economy.

Having thus described this invention, what l claim and desire to secure by Letters Patent is:

1. A dip tank heating apparatus comprising a dip tank heater; an article heating comartment; means to circulate gases of comustion through a' passage and through said heater; and means to circulate air in said heatin compartment and to circulate the same air around the outer surface of a portion of said passage, said passage for the gases of combustion being so arranged as to directly heat the outside walls of said compartment.

2. A combined dip tank heating apparatus comprising a dip tank heater; an article heating com artmeiit; means to circulate gases of combustion through a passage and through said heater; and means to pass air through said compartment, and to circulate the same air around the outer surface of a portion of said passage and then to recirculate the air through said compartment, said passage for the gases of combustion being arranged to conduct the heating gases in contact with the walls of said compartment, to maintain said compartment at constant temperature.

3. A combined. dip tank heating apparatus comprising a heating compartment having an air inlet and air outlet thereon; an air return duct formed in a wall of said compartment;

means to circulate and recirculate air through' said compartment and duct; a furnace related to said compartment; a portion of the gas passages'of said furnace being exposed in an air heating chamber, said return duct being adapted to conduct the returned air around the surface of said portion thereby heating the air; and a passage being connected to said heater to circulate gases of combustion around a dip tank; a gas return duct for returning the spent gases of combustion from the heater to the furnace for reheating the same; and means interconnected in said passages for circulating and recirculating the gases of comsaid gas circulating and recirculating passages being arranged to conduct the gases of combustion to the outside of the heating compartment as well as to maintain the walls of the compartment at constant temperature.

air to be circulated in the kiln dip tank heater, said 4. A combined pipe and dip tank heater com rising a heating compartment having an air inlet and outlet thereon; an air return duct formed in a wall of said com artment; and a fan discharging through sai air inlet, said air return duct being connected to the intake of said fan to recirculate the air through said compartment; a dip tank related to the heater; a furnace related to said compartment; a combustion box in said furnace; fire tubes communicating with an outlet passa e of said combustion box, said fire tubes being inclosed in an air heating chamber, connected to said air return duct so as to allow the heating of the air returned through said air return duct; a as duct for conducting gases of combustion rom the fire tubes to the tank heater; a gas return duct leading from said tank heater to the outlet passage of said combustion box for returning and reheating the spent gases from the tank heater; and means interconnected in the passage formed by said gas duct to cause forced circulation from the combustion box to the gas return duct thereby circulating the gases of combustion, said gas ducts and said gas return ducts being so arranged relatively to said heatin compartment as to radiate heat to the OIItSlC lB walls of the said compartment.

5. A combined pipe and dip tank heater comprising a heating compartment having an air inlet and outlet thereon; an air return duct formed in a wall of said compartment; and a fan discharging through said air inlet, said air return duct being connected to the intake of said fan to recirculate the air through said compartment; a dip tank related to the heater; a furnace related to said compartment; a combustion box in said furnace, fire tubes communicating with an outlet passage of said combustion box, said fire tubes being inclosed in an air heating chamber connected to said air return duct so as to allow the heating of the air returned through said air return duct; a gas duct for conducting gases of combustion from the fire tubes to the tank heater; a gas return duct leading from said tank heater to the outlet passage of said combustion box for returning and reheating the spent gases from the tank heater, said gas return duct extending adjacent the walls of said heating compartment, for heating said walls; and means interconnected in the passage formed by said gas duct to cause forced circulation from the combustion box to the gas return duct thereby recirculating the gases of combustion.

6. A combined pipe and dip tank heater comprising a heating compartment having an air inlet and outlet thereon; an air return duct formed in a wall of said compartment, and a fan discharging through said air inlet, said air return duct being connected to the intake of said fan to recirculate the air through said compartment; a dip tank related to the heater; a furnace related to said compartment; a combustion box in said furnace; fire tubes communicating with an outlet passage of said combustion box, said fire tubes being inclosed in an air heating chamber connected to said air return duct so as to allow the heatin of the air returned through said air return uct; a gas duct for conducting gases of combustion from the fire tubes to the tank heater; a gas return duct leading from said tank heater to the outlet passage of said combustion box for returning and reheating the spent gases from the tank heater; a portion 0t saic gas return duct being formed on the walls of said heating compartment for heating said walls; and a fan dis charging into the said gas duct and having its intake connected to the outlet of said fire tubes for circulating and recirculating the gases of combustion.

7. A combined pipe and dip tank heater comprising a base; a heating kiln formed on the base; a furnace on the kiln: a dip tank related to the kiln; a combustion box in said furnace; a passage for conducting ases of combustion from the furnace to the dip tank; said passage being disposed to radiate heat to the outside walls of said kiln, a return (11105. formed partly on the walls of the heating kiln to return the gases of combustion from the dip tank to the outlet of the combustion box and to heat the respective kiin walls; and means connected in said passage to produce forced circulation of the gases of combustion through said passage and return duct, said kiln having an air inlet and an air outlet thereon; a fan discharging through the air inlet; an air return passage formed in the top of the kiln for conducting the air from the air outlet to the intake of said fan. said air return duct being so formed as to circulate the air around a portion of said gas passage, thereby heating the air 8. In an apparatus for heating a liquid in which an article is treated and for preheating the article by the utilization of the same heating substance, comprising a combustion box for burning fuel therein, adapted to conduct the gases of combustion on a tortuous path; a plurality of fire tubes; a gas duct connecting the combustion box to said tubes; a fan having the intake thereof communicating with the outlets of the tubes; a dip tank heater; a duct connecting the tank heater to the discharge side of the fan; a return duct for conducting the spent gases of combustion from the tank heater to the outlet passage of the combustion chamber so as to allow the reheating and recirculation of said spent gases; a heating compartment adapted to receive the article therein, said compartment having an air inlet and an air outlet opening adjacent the opposite ends thereof: a fan, the discharge thereof being connected to the compartment inlet opening; an air heating chamber formed around the fire tubes, the outlet of the compartment communicating with the air heating chamber around the tube, the outlet of said last mentioned chamber being connected to the intake of the fan; andbaffles in the chamber around the tubes to deflect thefiow of air through said chamber, thereby causing the heating of the air by said tubes, said ducts for the gases of combustion being arranged on the walls of the kiln to heat said walls from the outside.

9. In combination with a dip tank heater and a kiln, a furnace comprising a combustion chamber, a mixing chamber communicating with the combustion chamber, a gas duct to conduct the products of combustion from the mixing chamber to the tank heater, a return duct to return the spent gases of combustion from the tank heater to the mixing chamber so as to draw into the mixing chamber fresh products of combustion from the combustion chamber to compensate for the heat given up by said returned spent gases, means to circulate the gases of combustlon, a portion of said first gas duct being exposed in an air heating-chamber, said chamber communicating with the interior of the kiln, means to circulate air through said air heating chamber and through said kiln, said gas duct and return duct being arranged in the wall of said kiln to heat the kiln walls from the out- 51 e.

In testimony whereof, I have hereunto set my hand at San Francisco, Calif., this 29th day of August, 1929.

FRANCIS G. WILLIAMS. 

